1. Field of the Invention
The present invention relates to a gas concentration control device, and in particular to a gas concentration control device that is used in a pressure vessel curing oven to control gas concentration inside an accommodation space thereof.
2. The Related Arts
In prior art, a de-voiding curing oven applies high pressure and high temperature to an adhesive material. The high temperature lowers the viscosity of the adhesive material and the high pressure removes voids that are existing in the adhesive material out of the adhesive material by means of pressure difference, or shrinks the voids contained in the adhesive material by means of the pressure difference, so as to effectively improve product quality and reliability. Such a prior art technique has been widely applied to semiconductor packaging processes, and currently, an industrial pressure vessel curing oven commonly used to process adhesive materials for bonding chips. The pressure vessel curing oven has an interior chamber that is connected a high pressure gas outside the curing oven to serve as a gas source. An electrical heating device is used to supply thermal energy that is required inside the curing oven. A driving motor is external to the curing oven and a fan arranged in a center of the electrical heating device is driven by the driving motor to rotate. The fan comprises an agitation device to cause the heated high temperature high pressure gas inside the curing oven to flow and thus spread uniformly, so that a semiconductor material placed in the curing oven can be uniformly heated.
The concentration of the gas inside the curing oven is difference for processes of different products. However, the conventional measurement and control device are generally of poor pressure endurability and are not useable in the high temperature and high pressure environment inside the curing oven. Improvement is desired in this respect.